Composition of matter containing urea and nitrates, process for its preparation and use



Patented Dec. 3, 1935 PATENT OFFICE COMPOSITION OF MATTER CONTAININGUREA AND NITRATES, PROCESS FOR ITS PREPARATION AND USE Walter H.Kniskern, Prince George County, Va.,

and Charles K.

Lawrence, Syracuse, N. Y.,

assignors to Atmospheric Nitrogen Corporation, York New York, N. Y., acorporation of New No Drawing. Application January 21, 1933,

Serial No. 652,923

11 Claims.

. This application is a continuation of our copending United Statesapplication Serial No. 611,232, filed May 13, 1932 and is related to our,copen ding United States application Serial No.

652,922, filed January 21, 1933.

In/our said applications Serial No. 611,232 and Serial No. 652,922, wehave described new compositions useful in the production of fertilizerscontaining'urea, ammonia and a nitrate salt such as ammonium nitrate orsodium nitrate. The invention of this application particularly relatesto compositions containing urea, ammonia, and nitrates, to processes fortheir preparation and use in the production of fertilizers and to amethod for the transportation of urea, ammonia and nitrates. Sodiumnitrate, ammonium nitrate and potassium nitrate,are examples of nitrateswhich may be utilized in carrying out this invention.

- The methods for the fixation of atmospheric I nitrogen recentlydeveloped make. available from J this sourcelarge amounts of ammonia forindustrial purposes and particularly for the production of fertilizers.In the ammonia synthesis process for the production of fixed nitrogen inwhich hydrogen is obtained from water gas or similar gases containingcompounds of carbon, large amounts of carbon dioxide are separated fromthe gas as-aby-product in the preparation of the hydrogen-nitrogen gasmixture required for the synthesis of ammonia. This carbon dioxide maybeutilized by combining it with the ammonia to form urea. The syntheticammonia may likewise be oxidized to nitrogen oxides and these oxidesabsorbed in bases such as sodium or potassium carbonate or sodium orpotassium hydroxide, to producesodium nitrate or potassium nitrate, or,

the nitrogen oxides may be converted to nitric acid for treatment withsodium, potassium or ammonium carbonates or hydroxide or with an- 40hydrous ammonia, to form sodium, potassium or ammonium nitrate. Thereare, therefore, available atsynthetic ammonia plants the severalproducts; ammonia, urea, and nitrates such as sodium nitrate, potassiumnitrate and ammonium nitrate.

The marketing of these separate products is, vhowever, attendedbydifficulties and expensive operations. The ammonia is obtained eitherin the form of liquid ammonia or of aqua ammonia. The liquid ammonia hasrelatively high vapor pressures at ordinary temperatures and the aquaammonia contains ,a considerable proportion of water, both of. whichfactors make the transportation of large quantities of ammonia diflicultand'expensive. With'respect to sodium,potassium and ammonium nitrate andurea, these materials are usually produced in aqueous solution and, inorder to obtain them as the solid, expensive evaporations must becarried on.

It is frequently desirable to prepare a fertilizer 5 containing bothphosphorus and nitrogen and this may be done by treating monocalciumacid phosphate materials, such as superphosphate or triplesuperphosphate, with ammonia. When relatively large proportions ofammonia are add- 10 ed to a superphosphate material, however, theammonia tends to cause water soluble andcitrate soluble P205 in thesuperphosphate to revert to a citrate insoluble form which is notconsidered available as plant food. It is often desirable, 15 however,to obtain a fertilizer product containing a. higher proportion ofnitrogen than may be obtained by treating a superphosphate material withammonia alone in an amount which does not cause excessive reversion ofP205. 20

It is, accordingly, an object of this invention to provide compositionsof matter comprising the nitrogen-containing products readily availableat synthetic ammonia plants (urea, sodium, potassium and ammoniumnitrate and ammonia), 25 which compositions may be convenientlytransported as liquids of low vapor pressure containing a relativelyhigh percentage of nitrogen. It is further an object of this inventionto provide a process for the economical preparation for 30transportation of urea, nitrates and ammonia in the form of liquidcompositions containing these valuable ingredients. Another object ofthe invention is to provide a process for the production of fertilizerswhich may contain a relatively 35 high proportion of nitrogen bytreating a monocalcium acid phosphate material, for example,superphosphate, triple superphosphate or mixtures containing the same,with a liquid composition comprising urea, a nitrate and ammonia. 40

We have discovered that the solubility of urea in ammoniacal liquids maybe modified by dissolving sodiumnitrate in the liquid. Thus we havefound that whereas solutions of 'urea in about 50%"aqua ammonia (asolution of ammonia 45 in water containing 50% NHs) saturated at 45 0.contain about 133 parts of urea for every 1 Y part of ammonia in thesolution, if sodium nitrate is added to such a saturatedurea-ammonia-water solution, additional urea may be dissolved so 50 thata solution containing about 1.61 parts of urea and 1.61 parts of sodiumnitrate for every 1 part of ammonia, which-does not salt out attemperatures above 4.5 0., may be prepared. Similarly, whereas asolution of urea in about 55 50% aqua ammonia saturated at C. containsabout 1.17 parts of urea for every 1 part. of ammonia, if sodium nitrateis added to the ureaammonia-water solution, a solution containing 1.33parts of urea and 0.59 parts of sodium nitrate for every 1 part ofammonia which does not salt out at temperatures above 2 C., may beprepared.

We have found that the same phenomenon holds true for anhydrous liquidammonia. as for aqua ammonia. Thus, at 2 C., a saturated solution ofurea in anhydrous liquid ammonia contains about 0.46 parts of urea forevery 1 part of ammonia whereas, if to this urea-ammonia solution sodiumnitrate is added, the solubility of the urea is increased so that asolution of urea and sodium nitrate in liquid anhydrous ammonia may beprepared containing 1.17 parts of urea and 1.17 parts of sodium nitratefor every 1 part of ammonia which does not salt out at temperaturesabove 2 C. A solution likewise may be prepared of urea and sodiumnitrate in anhydrous liquid ammonia containing 0.72 parts of urea and0.31 parts of sodium nitrate for every 1 part of ammonia which does notsalt out at temperatures above 2 C., and a solution may be preparedcontaining about 0.55 parts of urea and 1.24 parts of sodium nitrate forevery 1 part of anhydrous liquid ammonia which does not salt out attemperatures above 2.6 C.

Not only does the presence of the sodium nitrate increase the solubilityof the urea but we have discovered that the converse relationship holdstrue; i. e., that by dissolving urea in solutions of sodium nitrate inaqua ammonia or liquid anhydrous ammonia, the solubility of the sodiumnitrate in the liquid may be increased. Thus, for example, a solution ofsodium nitrate in about 50% aqua ammonia saturated at 4.5" C. containsabout 1.21 parts of sodium nitrate for every 1 part oi ammonia. Asstated above, by dissolving urea in the sodium nitrate-ammonia-watersolution a liquid composition containing 1.61 parts of urea and 1.61parts of sodium nitrate for every 1 part of ammonia which does not saltout at temperatures above 4.5 C., may be prepared. Sodium nitrate issoluble in liquid anhydrous ammonia to the extent of about 1.30 parts ofsodium nitrate for every 1 part of liquid anhydrous ammonia at atemperature of 6.7 C. A liquid composition may be prepared, however,containing about 1.37 parts of sodium nitrate and about 0.97 parts ofurea for. every 1 part of liquid anhydrous ammonia which does not saltout at temperatures above 6.7 C.

These phenomena discovered by us of the mutual influence of urea andsodium nitrate upon the solubility of each other in ammoniacal solutionseither in anhydrous liquid ammonia or in aqua ammonia are of importantpractical value since they make available compositions which retaintheir fluid state at ordinary atmospheric temperatures and contain ahigh proportion of nitrogen-bearing materials; 1. e., urea, sodiumnitrate and ammonia. Furthermore, these solutions do not present seriousdifliculties due to the separation of solid from the liquid underordinary conditions. Any solid material which may, under certaincircumstances, separate out may be redissolved by a slight warming ofthe solution. These highly concentrated solutions may, therefore, beeconomically utilized for the transportation of fixed ammonia. They areof practical value in the preparation of fertilizers by addition, forexample, to superphosphate. Since they contain but a relatively smallamout of water, they permit the direct production of commercially drygranular fertilizer products by adding the solutions'to superphosphate.They permit the production of phosphate fertilizers containing a highproportion of plant food. Since they contain a large proportion of totalnitrogen for a given amount of alkaline ammonia, the addition of thesesolutions to a superphosphate in amount such that the alkaline ammoniadoes not cause excessive reversion of available P205 in thesuperphosphate imparts to the resulting fertilizer a high nitrogencontent. The fertilizers thus prepared are in excellent physicalcondition and may contain nitrate-nitrogen, ammonia-nitrogen andurea-nitrogen.

An important characteristic of the urea-sodium nitrate-ammonia solutionsof this invention is their lower vapor pressures than the vaporpressures of liquid ammonia or of aqua ammonia of a correspondingconcentration. Liquid anhydrous ammonia has vapor pressures which rangefrom 4.2 atmospheres absolute at 0 C. to 11.5 atmospheres absolute at 30C. A solution comprising about 30.6 parts urea, 25.5-parts sodiumnitrate and 43.9 parts of anhydrous liquid ammonia which does not saltout at temperatures above -4 C. has a vapor pressure at 0 C. of about2.8 atmospheres absolute and at C. of 8.2 atmospheres absolute.Similarly, a liquid 30 composition comprising about 19.7 parts of urea,44.4 parts of sodium nitrate and 35.9 parts of liquid anhydrous ammonia,which does not salt out at temperatures above 2.6 C., has a vaporpressure at 0 C. of about 1.9 atmospheres absolute and at 30 C. of about5.7 atmospheres absolute. Aqua ammonia containing 50% NH; has a vaporpressure at 0 C. of about 1.1 atmospheres absolute and at 30 C. of about3.5 atmospheres absolute. A solution comprising about 15 40 parts ofurea, 32 parts of sodium nitrate and 53 parts of 50% aqua ammonia, whichdoes not salt out at temperatures above 1 C., has a vapor pressure at 0C. of about 0.6 atmosphere absolute and at 30 C. of about 2 atmospheresabsolute. The materially lower vapor pressures of the compositions ofthis invention greatly facilitate their handling during transportation,their storage and their manipulation in the preparation of fertilizers.Solutions of urea and sodium nitrate in anhydrous liquid ammonia andureasodium nitrate ammonia water compositions, particularlywater-containing compositions in which the water is in amount not morethan 40% by weight of the total liquid, which are substantiallysaturated with solid components at temperatures between about 30 C. and30 C. and particularly at about 0 C., are advantageous both becausetheir use in the treatment of superphosphate materials for theproduction of fertilizers permits of adding to the phosphate relativelylarge amounts of nitrogen-containing material for a given amount ofbasic ammonia and because of their relatively low vapor pressures, whichfacilitate their handling.

Urea, sodium nitrate and ammonia may be prepared for transportationand/or use in the preparation of fertilizers in the form of the-liquidcompositions of this invention by admixing dry solid sodium nitrate andurea with either liquid or gaseous anhydrous ammonia or with aquaammonia, the gaseous anhydrous ammonia being absorbed by the solids toform a liquid product. One of the solids may be added to a solution orslurry of the other in liquid or aqua ammonia. 7

aoaaevs In preparing aqueous compositions water solutions or slurriescontaining sodium nitrate and urea may be treated with anhydrous or aquaammonia or gaseous ammonia may be absorbed in the solution or slurry. Ingeneral, the compositions may be prepared by admixing the desiredproportions of the urea, sodium nitrate and ammonia, with or withoutwater, and any one or more of the components may contain proportions ofthe other components.

We have also discovered that the solubility of urea in ammoniacalliquids may be modified by dissolving ammonium nitrate in the liquid.

Thus we have found that whereas a solution oi urea in about 50% aquaammonia saturated at 10 C. contains 1.52 parts of urea for every 1 partof NH; in the solution, if ammonium nitrate is added to such a saturatedurea-ammoniawater solution additional urea may be dissolved in thesolution, so that a solution containing 1.35 parts or ammonium nitrateand 2.09 parts of urea for every 1 part of ammonia which does not saltout at 10 C. or above may be prepared.

We have found that the same phenomena hold true for anhydrous liquidammonia as for aqua ammonia. Thus at 14 C. a saturated solution oi! ureain the anhydrous liquid ammonia contains about 0.79 part of urea forevery 1 part of ammonia. If to this urea-ammonia solution ammoniumnitrate is added, the solubility of the urea is increased so that, forexample, a solution 01' urea and ammonium nitrate in liquid anhydrousammonia may be prepared containing 1.05 parts of urea and 0.58 part ofammonium nitrate for every 1 part of ammonia which does not salt out at14 C. or above.

Not only does the presence of the ammonium nitrate increase thesolubility of the urea but we have discovered that the converserelationship holds true; i. e., that by dissolving urea in solutions ofammonium nitrate in liquid anhydrous ammonia or in aqua ammonia, thesolubility of the ammonium nitrate in the liquid may be increased. Thus,for example, a solution of ammonium nitrate in about 50% aqua ammoniasaturated at 5 C. contains about 3.15 parts of ammonium nitrate forevery 1 part of ammonia. By dissolving urea in the ammoniumnitrateammonia-water liquor the solubility of ammonium nitrate isincreased so that, for example, a solution in 50% aqua ammonia of ureaand ammonium nitrate which does not salt out at 5 C. may be preparedcontaining about 1.18 parts of urea and about 4.05 parts of ammoniumnitrate for every 1 part of ammonia. This efiect of urea upon thesolubility of ammonium nitrate is also evident in solutions of thesesubstances in anhydrous liquid ammonia. A solution of ammonium nitratein anhydrous liquid ammonia saturated at 2 C. contains about 2.78 partsof ammonium nitrate for every 1 part of ammonia whereas a solution ofurea and ammonium nitrate in liquid anhydrous ammonia which does notsalt out at. -2 C. may be prepared containing 1.05 parts of urea and3.21 parts of ammonium nitrate for every 1 part of ammonia.

As in the case of the urea-sodium nitrateammonia solutions, an importantcharacteristic of the urea-ammonium nitrate-ammonia solutions of thisinvention, is their lower vapor pressures than that of liquid ammonia orof an aqua ammonia of a corresponding concentration. A solution whichdoes not salt out at temperatures above about 5 C. of urea-ammoniumnitrateammonia-water having a composition of 16.4%

3 urea, 56.3% ammonium nitrate, 13.9% ammonia and 13.4% water has avapor pressure ranging from 0.3 atmosphere absolute to 0.8 atmosphereabsolute for temperatures between C. and 30 C. Throughout this range ortemperatures the vapor pressure 01' this solution is less than 1atmosphere, whereas for an aqua ammonia of corresponding composition(about 50% aqua) the vapor pressure is from 1 to 3.6 atmospheres. Likuidanhydrous ammonia has a vapor pressure ranging from 4.2 to 11.5atmospher absolute for temperatures from 0 C. to 30 C. A solution ofurea and ammonium nitrate in liquid anhydrous ammonia which does notsalt out at -2 C. and containing 20% urea, 61% ammonium nitrate and 19%ammonia, has a vapor pressure of from 0.5 to 1.9 atmospheres absolutefor temperatures ranging from 0 C to 30 C. Solutions of urea andammonium nitratein anhydrous liquid ammonia which are substantiallysaturated with urea at a temperature below 30 C.', and particularly atabout 0' 0., and which contain about 1 part of urea to above about 2parts or ammonium nitrate, are particularly advantageous from theviewpoint of their relatively low vapor pressures. With water present,however, solutions of a low vapor pressure may be prepared containing ahigher ratio of urea to ammonium nitrate.

The solubility of potassium nitrate in ammoniacal liquids may beincreased by the addition of urea. and conversely the solubility of ureamay be increased by the addition of potassium nitrate. Thus, 'at 0 C. asaturated solution of urea in anhydrous liquid ammoni'a contains about0.49 part of urea. for every 1 part of ammonia, whereas, if to thisurea-ammonia solution potassium nitrate is added, the solubility of theurea is increased so that a solution of urea and potassium nitrate inliquid anhydrous ammonia may be prepared containing 0.59 part of ureaand 0.1 part of potassium nitrate for every 1 part of ammonia which doesnot salt out at temperatures above 0 C. A solution of urea and potassiumnitrate in anhydrous liquid ammonia may also be prepared containing 0.77part of urea and 0.27 part of potassium nitrate for every 1 part ofammonia which solution does not salt out at temperatures above about 7C.

A solution of potassium nitrate in anhydrous liquid ammonia saturated at0 C. contains about 0.1 part of potassium nitrate for every 1 part ofammonia. If, however, urea is dissolved in this solution of potassiumnitrate, the solubility of the potassium nitrate is increased so that asolution in anhydrous liquid ammonia may be prepared containing about0.46 part of urea. and about 024 part of potassium nitrate for every 1part of ammonia, which does not salt out at temperatures above about 0C.

In general the solutions of urea, ammonium nitrate and ammonia and urea,potassium nitrate and ammonia may be prepared in the manners hereindescribed for the preparation of ureasodium nitrate-ammonia compositionsby using solutions or slurries of ammonium nitrate or potassium nitrateor the solid salts themselves in place of the sodium nitrate orsolutions or slurries or the same. The invention is not limited,however, to such methods of preparing the compositions containingammonium or potassium nitrate.

By the addition or urea and ammonium nitrate or potassium nitrate toammoniacal liquids havcomponents at temperatures between aboutv of thecompositions containing sodium nitrate,

liquid compositions containing ammonia, urea and ammonium nitrate orpotassiumnitrate, which are substantially saturated with solid -30 C.and 30 C., and particularly at about 0' C., are advantageous bothbecause of their making possible the addition to a superphosphate ofrelatively large amounts of nitrogen containing material for a givenamount of basic ammonia and because of their relatively low vapor pressures, which facilitate their handling and transportation.

The urea-ammonia-nitrate compositions of this invention may be readilytransported in a transportable package comprising a container and theliquid composition. Due to the material lowering of the vapor pressuresof ammoniacal liquids by dissolving urea and sodium nitrate, potassiumnitrate or ammonium nitrate therein, the containers in which the liquidsare shipped are not subjected to the relatively higher vapor pressuresof the ammoniacal liquids themselves. In many cases relatively highvapor pressures of ammoniacal liquids at ordinary atmospherictemperatures which, without the urea and a nitrate being present arematerially above atmospheric, may be lowered by dissolving in theammoniacal liquid urea and a nitrate to such an extent as to permit itstransportation and handling in low pressure containers, whereas anammoniacal liquid of corresponding composition without these materialsbeing present, would require special equipment for its transportation.It is of advantage to dissolve in ammoniacal liquids having vaporpressures materially above atmospheric pressure at ordinarytemperatures, urea and a nitrate in amount at least suillcient to lowerthe vapor pressure of the ammoniacal liquid to about atmospheric atordinary atmospheric temperatures.

The following examples are illustrative of methods of preparing thesolutions of this invention. Throughout this specification and in theclaims, the proportions of materials are referred to as parts by weight:v

Example I.--A substantially anhydrous liquid composition may be preparedby mixing about 54 parts of solid urea with about 46'parts of liquidanhydrous ammonia. These materials form a slurry which at -2 C. containsabout 48 parts of undissolved CO(NH2) 2.NH3. To the foregoing mixtureare then added about 54 parts of sodium nitrate for each 100 parts ofthe mixture. After thorough admixing a substantially homogeneouscomposition will form at temperatures of about '-2 C. and above. At 30C. the composition has a vapor pressure of about 6 atmospheres absolutewhich is equivalent to the pressure of about a 62% aqua ammonia at thesame temperature.

Example II.About 61.5 parts of solid urea are admixed with about 38.5parts of liquid anhydrous ammonia. The mixture thus obtained wouldcontain about 60 parts of undissolvedC0(NHz) 2.NH3 at a temperature of45 C. About 41 parts of water are then added to 100 parts of theforegoing composition and the resulting mixture would contain about 10.5parts of undissolved urea at 4.5" C.

. About 61.5 parts of solid sodium'nitrate are then added to about 141parts of the urea-ammoniawater composition and admixed therewith. Thismixture forms a homogeneous composition which will not salt out atatemperat'ure of about 4.5 C.

or above. At 30 C. the composition has a vapor .5 pressure of about 1.8atmospheres absolute which is equivalent to the vapor pressure of about38% aqua ammonia at the same temperature.

A similar composition may be prepared by admixing about 61.5 parts ofsolid sodium nitrate l0 and about 38.5 parts of liquid anhydrous ammoniaand then adding to 100 parts of this mixture about 41 parts of water.The resulting mixture at a temperature of 4.5 C. would contain aboutparts of undissolved sodium nitrate. Upon adding 15. about 61.5 parts ofsolid urea to about 141 parts of the sodium nitrate-ammonia-watercomposition a homogeneous product results which does not salt out attemperatures above about 4.5 C.

Example III.-About 58 parts of solid sodium .nitrate and about 42 partsof liquid anhydrous ammonia are admixed to form a mixture in which at6.7 C. about 3.3 parts of the sodium nitrate remain undissolved. To 100parts of this mixture are added about 41 parts of solid urea. Theresuiting homogeneous product does not salt out at temperatures aboveabout 6.7 C. At C. this composition has a vapor pressure of about 5.5atmospheres absolute which is equivalent to the vapor pressure of about60% aqua ammonia at 30 30 C.

Example IV.--About 51 parts of a urea-water composition containing about39 parts of urea, such as may be obtained in a process for the synthesisof urea from ammonia and carbon dioxide, are mixed with about 51 partsof sodium nitrate (calculated on the dry basis, although the nitrate maycontain adhering mother liquor as it is recovered from solution in aprocess for its manufacture), about 40 parts of anhydrous liquid am- 40monia and enough water to bring the total weight of the mixture up toabout 170 parts, which requires the addition of about 28 parts of water,making a total of about 40 parts of water in the 170 parts of solution.

The solution of this example may be utilized in the preparation of afertilizer as follows: About 890 parts of a superphosphate containing18% P205, 100 parts of ammonium sulfate, 160 parts of muriate of potash(containing the equivalent of 50% K20) and 680 parts of an inert fillerare mixed together. About 1'70 parts of the foregoing urea-sodiumnitrate-ammonia-water composition are then sprayed onto the mixturewhile it is being agitated in, for example, a rotating drum. Theresulting product is in excellent physical condition immediately afterammoniation and also after cooling to atmospheric temperature. Thefertilizer thus obtained contains approximately 4% N, 8% P205 and 4% mo.About 23% of the total nitrogen of the fertilizer comes from the urea,about 10% is nitrate nitrogen and about 8'! is ammonium nitrogen.

Example V.--About 47 parts of substantially dry sodium nitrate and 47parts of substantially dry urea are dissolved in 40 parts of liquidanhydrous ammonia. About 135 parts of this composition are then added ina suitable manner to a mixture containing about 890 parts ofsuperphosphate, 8'7

arts of ammonium sulphate, 160 parts of 'potassium sulfate and 730 partsof inert filler such as sand. The resulting fertilizer product is ingood physical condition both immediately after admixing the urea-sodiumnitrate-ammonia liquor with the solid materials and also after cooling.The

agitated in a rotating mixer:

Parts about Superphosphate 890 Potassium sulfate (50% K10) 160 Sand 638The resulting fertilizer mixture, which is in good physical conditionimmediately after ammoniation and also after cooling to roomtemperature, contains 6% N, 8% P20: and 4% K20. The nitrogen is presentin the following forms:

Per cent Ammonia nitrogen 3.3 Nitrate nitrogen 1.5 Urea nitrogen 1.2Total nitrogen 6 Example VII.--A composition containing urea, potassiumnitrate, ammonia and water may be prepared by mixing the followingmaterials: (a) 41 /2 parts of a urea-water composition containing about32 parts of urea such as may be obtained from the synthesis of urea fromammonia and carbon dioxide; .(b) about 36 parts of a solution of about 6parts of potassium nitrate in water; and about 40 parts of anhydrousammonia. The liquid composition formed by mixing the above ingredientsdoes not salt out at temperatures above 3 C. and has, at 30 C. a vaporpressure of about 2.9 atmospheres absolute, approximately equal to thevapor pressure of 46% aqua ammonia at this temperature.

A fertilizer may be prepared by mixing about 120 parts of the abovedescribed liquid composition with a mixture of the following materials:

. Parts Superphosphate 890 Ammonium sulfate 152 Muriate of potash 155Inert filler 685 The resulting fertilizer mixture is in good physicalcondition both immediately after ammoniation and also after cooling. Itcontains about 4% N, 8% P205 and 4% K20.

Example VIII.--About 10 parts of potassium nitrate and 18 parts of ureaare dissolved in about 40 parts of liquid anhydrous ammonia forming'asolution which does not salt out at temperatures above about 3 C. About68 parts of this solution are then admixed with the followingingredients:

Parts Superphosphate 890 Ammonium sulfate 180 Potassium sulfate 150 Sand710 al materials such as phosphate, ammonium sulfate, potassiumchloride, etc. or any two or more of these materials which in themselvesare valuable fertilizers, may be incorporated with theurea-ammonia-nitrate solutions before 5 they are added to the phosphatematerial, or they may be incorporatedwith fig Ph sphate material before,after or simultaneously with the treatment with the urea-ammonia-nitratecompositions. Also solutions containing urea and two or more nitratesmay be prepared and used in accordance with this invention, as forexample, ammoniacal solutions of urea, sodium nitrate and potassiumnitrate or of urea, ammonium nitrate and sodium or potassium nitrate.when in the appended claims reference is made to a solution saturatedwith the solid components" at a given temperature, it is intended torefer to a solution which contains an amount of urea and nitrate, suchas sodium, potassium or 20 ammonium nitrate, such that a solid phasecontaining one or more of these materials does not separate at the giventemperature, but which upon cooling, to a lower temperature depositssolid urea and/or solid nitrate or a solid comprising either urea ornitrate or both.

We claim: I,

1. As a new composition of matter, a liquid comprising urea, a nitrateand a substantial proportion of ammonia, said liquid containing anamount of at least one of said urea and nitrate dissolved therein inexcess of that necessary for saturation of the liquid in the absence ofthe other.

2. As a new composition of matter, a solution of both urea and a nitratein an ammoniacal liquor containing a substantial proportion of ammonia,said solution being substantially saturated with at least one of saidurea and nitrate at a temperature between about -30 C. and 30 C.

3. As a new composition of matter, a liquid comprising urea, sodiumnitrate and a substantial proportion of ammonia, said liquid containingan amount of at least one of said urea and sodium nitrate dissolvedtherein in excess of that neces sary for saturation of the liquid in theabsence of the other.

4. As a new composition of matter, a substantially anhydrous solution ofurea and sodium nitrate in ammonia, said solution containing anamount-of at least one of said urea and sodium nitrate dissolved thereinin excess of that necessary for saturation of the solution in theabsence of the other.

5. A process for the preparation for transportation of urea and ammoniawhich comprises dissolving both urea and a nitrate in an ammoniacalliquor containing a substantial proportion of ammonia, said materialsbeing employed in proportions such that the resulting liquid compositioncontains an amount of at least one of said urea and nitrate in excess ofthat necessary for saturation of the ammoniacal liquid in the absence ofthe other.

6. A process for the preparation for transportation of urea and ammoniawhich comprises dis- 55 solving both urea and sodium nitrate in anammoniacal liquor containing a substantial proporportion of ammonia,said materials being employed in proportions such that the resultingliquid composition contains an amount of at least one of said urea andsodium nitrate in excess of that necessary for saturation of theammoniacal liquid in the absence of the other.

7. A process for producing a fertilizer which comprises treating a solidacidic fertilizer ms.-

terial with a solution of a nitrate and urea in an ammoniacal liquidcontaining a substantial proportion of ammonia, said solution containingan amount oi at least one of the said nitrate and urea dissolved thereinin excess of that necessary for saturation ,of the ammoniacal liquid inthe absence of the other.

8. A process for producing a fertilizer which comprises treating asuperphosphate material with a solution of a nitrate and urea in anammoniacal liquid containing a substantial proportion of ammonia, saidsolution containing an amount of at least one of the said nitrate andurea dissolved therein in excess of that necessary for saturation of theammoniacal liquid in the absence of the other. e I

9. A process for producing a fertilizer which comprises adding to andmixing with a monocalcium acid phosphate material a solution of bothurea and a nitrate in an ammoniaoal liquor containing a substantialproportion of ammonia, said solution prior to addition to said phosphatematerial being substantially saturated with at least one ofsaidureaandnitrateat atemperature between about 30 C. and 30' C.

10. A process for producing a fertilizerwhich comprises treating a solidacidic fertiliser material with asolutionofsodiumnitrate andureainanammoniacal liquid containing a substantial proportion of ammonia, saidsolution containing an amount of at least one of the said sodium nitrateand urea dissolved therein in excea of that necessary for saturation ofthe ammoniacal liquid in 1 'comprises treating a superphosphate materialwith a solution of sodium nitrate and urea in an ammoniacal liquidcontaining a substantial pro- 15 portion of ammonia, said solutioncontaining an amount of at least one of the said sodium nitrate and ureadissolved therein in excess of that necessary for saturation of theammoniacai liquid in the absence of the other.

WALTER H. KNIBKERN. CHARLES K. LAWRENCE.

